两级运放中共模反馈电路的分析与设计  

Design and Analysis of a New Common Mode Feedback Circuit for Two-Stage Operational Amplifier

作　　者：连全文[1] 冯全源[1] 

机构地区：[1]西南交通大学微电子研究所,成都610031

出　　处：《微电子学》2010年第1期29-31,36,共4页Microelectronics

基　　金：国家自然科学基金资助项目(10876029)

摘　　要：在两级共源共栅CMOS运算放大器中,设计了一种新的共模反馈电路。这种电路克服了一般共模反馈电路存在的限制输出摆幅的缺点,在稳定电路直流工作点的同时,能有效提高电路的输出摆幅。通过对共模电路结构的分析,证明了其功能原理的正确性。基于0.18μm(3V)CMOS工艺库,用Hspice软件对电路结构进行了仿真验证。结果显示,电路低频增益达到120dB,功耗不到0.24mW。A novel common mode feedback （CMFB） circuit was designed for 2-stage cascode CMOS operational amplifier, in which cascoded-Miller compensation was used. The proposed CMFB circuit solves the problem of limited output swing, which is inherent to CMFB circuit, and stabilizes the DC voltage at normal operating point. The structure of CMFB circuit was analyzed. Hspice simulation based on 0. 18 /Lm CMOS 3 V mixed signal process showed that the circuit had a DC open gain up to 120 dB, with less than 0. 24 mW of power.

关 键 词：共模反馈电路 折叠共源共栅电路 运算放大器 

分 类 号：TN432[电子电信—微电子学与固体电子学] TN722